Step 1:
Fold an a4 or a5-size paper in half three times, fold a second paper also in half three times, but with the third fold into an angle of 90 degrees.

Step 6:
Fold and glue the model in a rectangular shape.

Step 5:
Glue the other three plus-shapes and two angled beams to the model.

Step 2:
Make eight beams of each type.

Step 4:
Glue a plus-shape to two angled beams.

Step 3:
Glue the eight flat beams into a plus-shape  (+)

Step 10:
Repeat steps 8 and 9 eight times.
Then fold four models in half over the lenght, so you get 4 larger planks and 4 smaller ones.

Step 8:
Fold an a4 or a5 paper in half.

Step 9:
Fold in half

Step 7:
And this is the base of the tower.

Step 16:
Lay two papers on top of each other and prefold them both in once over these pink lines.

Step 15:
The two paper squares used for the floor are 1,5x1,5 A4 or A5 papers. And the two squares for the roof are 1x1 A4 or A5 papers.

Step 12:
Glue the other six planks and two angled beams to the model.

Step 11:
Glue a smaller and a large plank to two angled beams.

Step 14:
And this is the cabin.

Step 13:
Fold and glue the model into a rectangular shape.

Step 21:
Glue / tape four a4 or a5 papers together.
Fold this long rectangle in half three times. Make two of these long planks.

Step 19:
Slide both models together.
I used zig zag folded paper strips to make the model stronger, see photo.

Then repeat steps 16 to 19 with the two smaller paper squares.

Step 20:
And the roof and floor are also ready....

Step 18:
Glue or tape the edges of the corners together, see marked areas.
Repeat steps 17 and 18 on the other paper.

Step 17:
Pull both papers apart, the upper paper is for the inside and the lower paper will fit exactly around it.
Fold the four corners inwards and the edges straight upwards over the prefolded lines.

Step 22:
Fold an a4 or a5 paper in half.

Step 28:
Glue one and a half a4 or a5 papers together. Then fold the large paper in half three times.
Make two long planks like this.

Step 25:
This should be the shape of the two long planks.

Step 26:
Glue the 14 short planks to the two long ones. Two planks are glued on each corner, next to the prefolded lines.

Step 24:
Prefold the two long planks in the shape of the floor, see pink line. On the left is an opening for the ladder.

Step 23:
Fold in half three times, in this direction.
Make 14 of these planks.

Step 29:
Prefold and cut an a4 or a5 paper in half.
Then fold this smaller paper in half, see pink line.

Step 27:
And the balcony fence is also ready....

Step 30:
Fold the model in half three times, in this direction.
Make six of these ladder steps.

Step 31:
Glue the six steps to the two long planks.

Step 32:
And the ladder is also done.